This section provides background information related to the present disclosure and is not necessarily prior art.
Articles of footwear typically include a sole structure that provides a layer between the foot on which the article of footwear is worn and a ground surface. The sole structure prevents the foot from contacting the ground surface and provides a degree of cushioning to the foot during use. The sole structure typically includes an outsole that contacts the ground surface and a midsole that supports, stabilizes, and cushions the foot. A polymer foam material may form the midsole to provide a level of cushioning that minimizes the forces felt by the foot when the outsole strikes the ground surface.
While traditional midsole materials, such as polymer foam materials, provide a degree of comfort and stability, such polymer foam materials are typically tailored to provide a specific type of cushioning and are generally limited in that regard. For example, stiffer foam materials provide a more responsive feel during use but are less capable of absorbing impacts. Conversely, softer materials are less responsive but provide a greater degree of cushioning and are therefore better suited than stiffer materials for applications that favor impact absorption over responsiveness. Accordingly, providing a sole structure with more than one type of cushioning system provides an article of footwear with both a responsive feel and the ability to absorb impacts during use.
In an effort to balance responsiveness and cushioning, footwear manufacturers typically provide a sole structure with more than one type of cushioning. For example, a midsole may be formed from a polymer foam material that is used in conjunction with rubber posts or resilient members. The posts provide a responsive feel during use while the polymer foam provides cushioning. While rubber posts or other resilient members may be used in conjunction with polymer foam, other cushioning systems such as fluid-filled bladders may alternatively be used in conjunction with polymer foam depending on the particular application.
While sole structures of conventional articles of footwear may include more than one type of cushioning system, such systems are typically separate and independent from one another. Accordingly, these systems separately provide the article of footwear with responsiveness and cushioning and only cooperate with one another once assembled into the sole structure.
Corresponding reference numerals indicate corresponding parts throughout the drawings.